Device for drawing billet and bar stock



D- 17, 1963 H. UEBING ETAL 3,114,276

DEVICE FOR DRAWING BILLET AND BAR STOCK BY #my/2Mb,

AT TOR/VE YS Dec. 17, 1963 H. UEBING ETAL DEvIcE RoR DRAWING BILLET AND BAR sTocK FiledJune 20. 1960 5 Sheets-Sheet 2 INVENToR. #EWR/CH (/f-//vg M25/gym ATTORNEYS Dec. 17, 1963 H. UEBING ETAL 3,114,276

DEVICE FOR DRAWING BILLET AND BAR STOCK Filed June 20. 1960 3 Sheets-Sheet 5 ATTORNEYS United States Patent O DEVECE FOR DRAWING liLLET AND BAR STCK Heinrich Uebing, Lintori, Bezirk, Dusseldorf', Erich Bretschneider, Dusseldorf-Eher, Aii Binder-nagel, Bremen,

and Karl Jurczyk, Blankenstein (Ruhr), Germany, as-

signors to Friedrich Kocks GmbH-l., Dusseldorf,

Germany Filed .lune 20, 1960, Ser. No. 37,205 Claims priority, application Germany July 31, 1956 3 Claims. (Cl. 78-13) The invention relates to a device serving to draw and to reduce the cross-sectional area of billet, bar or tube stock by forging it under the action of two opposed movable dies symmetrically driven by crank or eccentric mechanisms and working simultaneously on a longitudinally restricted portion of the stock, which dies are pivoted and capable of rolling upon the work during the operative portion of their approach to each other, forming it in the process, at the same time moving towards the unforrned end of the work, taking the work with them, and then withdrawing from each other again, clearing the work, and returning to their original position, so as to keep reaching fresh portions of stock with each repetition :of this cycle of operation.

This application is a continuation-inpart of application Serial No. 673,635 tiled on July 23, 1957, and now abandoned.

ln that application, the motion of each of the two dies is effected for exampie by means of two eccentrics or crank pins, one of which acts upon the die -directly near one of its ends, while the other is joined to the other end of the die by a connecting rod. The eccentric or crank pin acting directly upon the die consequently moves it with a component transverse to the direction of feed and in that direction. In another known embodiment of such a draw-forging device, the dies are joined by connecting rods to two crank or eccentric pins each to form a quadrilateral linkage, while for unique determination of each die position and to generate the feed motion, each die is in addition connected to a third connecting rod whose other end is either connected to a third crank or eccentric drive or else articulated at some suitable stationary point. While two connecting rods driven by crank pins or eccentrics carry the die towards and away from the center-line of the work, the third connecting rod pushes the die to and fro in the same rhythm.

Experience with known draw-forging devices of the kind referred to has shown that dies driven by three connecting rods in the manner described above yield higher forming efficiency, owing to independence of the feed movements of the dies from their motions transverse to the work, than dies mounted directly on an eccentric, and permit hiher rates of advance of the work. They also permit more simple adaptation to dierent forming problema.

lt is also known that several draw-forging devices, each equipped with a pair of pivoted dies, may be placed one foilowing another in such manner that the several pairs Aoscillate relative to the work in intersecting planes. While it is theoretically possible in this way to reduce the section of the stock, not only in one direction, but in several, the forming accomplished in a following device does not fail to react upon the previous deformation in the preceding device. Even for small area reductions, therefore, it becomes difficult to adapt the individual deformations of the work to the intended total deformation. On the other hand, in case of major area reduction in the following device as well, changes will occur in the surfaces not being formed in that pass, rendering the Work defective.

Finally, it is likewise known that several pairs of oscillating dies may be so mounted and actuated in one and the same draw-forging device that they lie between identical planes perpendicularly intersecting the center-line of the work, and, oscillating in mutually perpendicular planes, act upon the work simultaneously, so that as they roll their working surfaces upon it, they form a closed aperture in one cross-sectional plane at a time, which plane travels the length of the working surfaces in operation.

In further development of the last-mentioned drawforging device, specifically in attempts to adapt it to the forming of blooms, billets, bars and the like stock, it has proved that the use of such closed passages is disadvantageous in many cases. Since the material being formed in the closed passage cannot iow laterally, very high forging resistances arise, with resulting high power consumption; besides, when exceptionally high forming pressures are used, the material shows a tendency to enter under that pressure into the gap remaining open ahead of the closed passage between the neighboring dies, and this may lead to breakdown in operation or else to formation of lengthwise fins on the surface of the material.

To avoid these disadvantages, according to the invention, two pairs of pivoted dies operating in directions perpendicular to each other are to act on the work alternately, and not-as in any of the known devices-at successive locations, but collectively between the same two planes perpendicular to the axis of feed, opposing each other by pairs acting in perpendicularly intersecting directions. Contrary to devices with dies acting simultaneously on like lengthwise portions of the stock, this provides for keeping the work always held between two opposed dies, ensuring its positive uninterrupted lengthwise A advance.

However, since pairs of tools of the kind referred to, acting alternately in different, mutually perpendicular directions, where each pair advances the stock by a certain distance in each forming operation, cannot all act on identical lengthwise segments of the work, the shape leaving the dies would not, owing to successive widening in different directions, be of perfectly uniform cross section throughout its length, but would vary slightly at intervals, and fail to exhibit the desired smooth surfaces. Nor can this disadvantage be overcome merely by so constructing the dies, in known manner, that they will form Vthe work chieiiy during the first portion of their approach only, Whereas upon further approach they apply little pressure and act primarily to smooth the surface of portions of stock already reduced in section to almost the desired final dimension.

For if the feed is rapidas is desirable with a view to outputthen the intervals of variation in section to be acted upon by the smoothing portion of the dies are cornparatively long, so that satisfactorily smooth forged surfaces cannot be achievedl by the known method of iso designing the working surfaces of the dies in their smoothing portionwhich in that case will meet the main forming portion in an edgee-that the said smoothing portion will roli upon the surface of the work in a plane parallel to the axis, unless the dies were specially prolonged and provided with a disadvantageously long smoothing portion.

But a product with satisfactorily smooth surfaces and exactly uniform cross-sectional shape over its entire length is achieved in the draw forging of bar, billet or tube stock, even with comparatively short pivoted dies, if, according to the invention, .pressure acting alternately in two directions at right angles to each other between identical transverse planes upon two opposite sides of the Work at one time, and acting simultaneously in the direction of feed, intermittently displaces portions of niaterial from the full stock section forward and thereby, while at the same time feeding the work, reduces its crosssection below the desired final dimension in the direction of pressure, and simultaneously enlarges it beyond that dimension perpendicular to the direction of pressure, then bringing it to final size in both directions by eliminating the enlargements.

A draw-forging device suitable for the practice of this method has two pairs of dies actuated contrary to each other, arranged between identical transverse planes bounding their extreme positions and in axial planes perpendicularly intersecting each other, which pairs, according to the invention, act upon the work alternately, their dies being designed in such manner that the smoothingy portion of their working surfaces, meeting the main forming portion in an edge in known manner, consists of two segments, of which the one adjacent to the edge approaches the corresponding segment of the "opposed die to within a distance smaller than the final dimension of the work, while the segment at the exit end, at closest approach of the two dies of a pair to each other, is at a distance equal to the final dimension of the work from the corresponding segment of the Working surface of the opposite die.

The aim achieved by this conformation of the dies is that between the parts of the smoothing portions adjoining the main forming portions of the working surfaces of each two opposed dies, there is at first a more pronounced deformaton of the work in one direction than the nal section would require, accompanied by a lengthwise drawing, as well as some enlargement in the other transverse direction. During the ensuing working stroke of the other pair of dies, 90 away around the centerline of the work, the segments of the smoothing portion near the exit end will then encounter the portions of the work broadened beyond the final dimension, and, while eliminating this broadening, will correct the one-dimensional reduction of section caused by the first pair of dies, through a broadening effect in the first direction. In this way, then, the broadening effected at the end of each working stroke of one pair of dies, alters the stock left too at in one direction and too wide in the other direction by the preceding working stroke of the other pair of dies, in such manner that when it leaves the dies, it has the correct final dimensions in both directions.

The segments of the smoothing portion of the working surfaces may meet in an abrupt turn, or there may be a gradual transition from one to the other.

For completeness, be it noted that there are known forging machines in which a plurality of pairs, distributed between identical transverse planes about the centerline of the work, of hammers actuated contrary to each other, are allowed to act on the work successively, the work being advanced by means of a special feed while being hammered. In such hammer machines, however, neither are the working surfaces of the hammers subdivided into a main forming and a smoothing portion, nor are means provided for the purpose of equalizing the irregularities occurring-especially in rapid feed-on the section and surfaces of the work, by temporarily successive Working of the stock in different axial planes.

The device according to the invention will now be more fully described with reference to the accompanying drawings, but it should be understood that these are given by way of illustration and not of limitation and that many changes in the details may be made without departing from the spirit of the invention.

In the embodiment shown, in order to achieve a high forming efficiency, each pivoted dieV is moved relative to the work by two powered eccentrics or cranks, each by way of a connecting rod, and receives its advance and return movements from a third connecting rod with a stationary bearing.

In the drawings,

FIG. 1 shows a cross-sectional view of the device, with work in place;

FIG. 2 shows a lengthwise section through the device and the work along the line II-II in FIG. 1;

FIGS. 3a and 3b show two working positions of the 33 and 34 of the feed eccentrics.

f' ing one working stroke.

two pairs of pivoted dies relative to stock of square crosssection, where the vertically oscillating pair of dies is in engagement with the work under a and the horizontally oscillating pair of dies under b;

FIGS. 4a and 4b show the working positions correspending to FIGS. 3a and 3b for two pairs of dies acting on stock of round cross-section;

FIGS. 5a and 5b show pairs of pivoted dies in side view, drawn to a larger scale, with main-forming portions each meeting a smoothing portion in an edge, the forming portion being in engagement with the work in FIG. 5a and the smoothing portion being in such engagement in FIG. 5b;

FIG. 6a, further enlarged, shows a pair of pivoted dies in side View with subdivided smoothing portions of the working surfaces, and partially formed work between them;

FIG. 6b shows the work shown in FIG. 6a as seen from above at the same stage of the operation.

In the draw-forging device of FIG. 1, a common source of power (not shown), by way of a coupling 6 and spur gears, 7, 3, 9, 9 and 7, 10, 10' respectively, drives two similar mutually parallel eccentric shafts 1, 1 and 2, 2', respectively, of each die 5 of a vertically oscillating pair, the said shafts being located one behind the other in the direction of operation, while the eccentric shafts 11, 11' and 12, 12', likewise placed one behind another in pairs, of the horizontally oscillating pair of dies 17, are each driven by a pair of bevel gears 1S, 19 and 18', 19', and 2), 21 and 20', 21', respectively, from eccentric shafts 1, 1' and 2, 2. The dies 5 and 17 have projections 22 with lateral sliding surfaces by which they are guided in the housing to relieve the eccentric shafts. The dies 5 are suspended from eccentric shafts 1, 1 and 2, 2', essentially determining their motions perpendicular to the work, by connecting rods 3, 3 and 4, 4'. A third connecting rod 3" or 4" engaging the die by its exit end is mounted on an additional eccentric shaft 13 or 14. These eccentrics 13 and 14 primarily effect the forward and return strokes of dies 5. They are driven from eccentric shafts 1' and 2 by pairs of gears 15, 15' and 16, 16'.

Dies 17 are suspended in just the same way as dies 5, by two connecting rods 31 and 32 from eccentric shafts 11, 11' and 12, 12', and each connected by a third connecting rod (not visible in the drawings) to the shafts These eccentric shafts are driven from eccentric shafts 11' and 12' by pairs of gears 35, 35 and 36, 36'.

FIG. 5a, in a larger scale than FIG. 2, shows a pair of pivoted dies 5 in a position in which the main-forming portion 23, shaped substantially in a circular arc, of the working surfaces is acting on the work. The smoothing portion 25 of the working surface, joining the forming portion in an edge 24, is so shaped, in relation to the die motion imposed by the eccentrics, as to produce no substantial change in the section of the work, but only to compensate the irregularities resulting on the surfaces of the work from the intermittent operation and alternating action of the pairs of dies upon them, thus smoothing and then polishing the surfaces. FIG. 5b shows the position of the dies during this equalizing and smoothing process.

FIG. 6a, in further enlargement relative to FIGS. 5a and 5b, shows the conformation of the working surfaces of the dies, in particular the smoothing portions thereof, whereby the work is subjected to a stepwise differential height reduction in the direction of operation of the pair of dies currently in engagement. For the sake of greater clarity, an embodiment is illustrated wherein the segments A and B of the smoothing portion of the die surfaces meet in an abrupt offset. The dies are shown in a position in which they have reduced virtually the portion of the work extending from 28 to 29 below its final dimension in height. The distance from 28 to 29 approximately corresponds to the advance of the dies and the worl: dur- The shape of the work after completion of a working stroke is indicated by solid lines in FIGS. 6a and 6b. Prior to the working stroke, the work had a shape indicated as far as point 29 by interrupted lines. Between points 29 and 30, there is an increase in height (FIG. 6a), extending beyond the final dimension h by the amount of the shaded area and corresponding to a similarly shaded over-reduction in the direction of the width b (FIG. 6b). This over-reduction resulted from displacement of stock between working segments A during a preceding stroke.

The pair of dies indicated in FIG. 6a first displaces the stock present between the solid and the interrupted lines, as much of it as lies between points 28 and 29 being reduced below the final dimension h in segment A of the smoothing portion. In the direction perpendicular (FIG. 6b) to this forming direction, the work is at the same time spread from the shape represented by interrupted lines to that drawn solid, while some of the displaced stock is displaced somewhat towards the exit end, thus drawing the work. When the dies have about reached the position shown in FIG. 6a, then for example a portion of stock located at 28 before commencement of the deformation will have moved to 29, and one located at 29 will have moved to 30. The second, diverging segment B of the smoothing portion of the dies has therefore yet to displace the shaded stock bounded by the dot-dash lines in FIG. 6a, in order to attain the altitude l1 of the final shape.

ln the other direction (FiG. 6b), in the course of the deformation shown, a portion originally located at 28 will likewise have been advanced to 29, and one located at 29k to 30. In the region between points 29 and 30, that is, the work has the shape indicated by the dashed lines, as yet too narrow relative to the final width b. Now when the dies displace the material indicated by shading in FIG. 6a between points 29 and 30, the resulting spread will till up the area shaded in FIG. 6b, so that iinaily, at the end of the working stroke, the work will be of height l1 in one direction and width b in the other direction, its correct section dimensions.

In the next working stroke, the pair of dies oscillating perpendicular to those indicated in FIG. 6a acts on a portion of the work located farther back by the length of the stroke, and the process described repeats itself in exactly the same way. Now the solid lines represent the work prior to forming; they match the lines drawn dashed for the preceding working stroke, if FIGS. 6a and 6b are interchanged.

What we claim is:

1. In an apparatus for the draw-forging of ductile metallic stock, in combination, support means; at least two pairs of opposing jaws displaceable on said support means in respective mutually perpendicular planes for longitudinally advancing said stock; and drive means for alternately dispiacing said pairs of jaws into engagement with said stock and imparting to the jaws of each pair a rocking motion for squeezing said stock in a direction transverse to its longitudinal dimension in the respective plane, said pairs of jaws being overlappingly engageable with successive longitudinal zones of said stock for concentrating the squeezing action at successive locations therealong, the jaws of each pair being convex in the direction of said stock and having an arcuate first shaping surface whose distance of closest approach is less than the final dimension of said stock in the respective plane and an arcuate second shaping surface with a center of curvature different from that of said first surface and adjoining said first surface at a ridge, said second surface having a distance of closest approach equal substantially to said tinal dimension whereby an enlarged portion of said stock formed by the first surface of the other pair of jaws is restored to said final dimension by a successive working stroke.

2. The combination as defined in claim 1 wherein said rst and second surfaces of each of said jaws are offset one from the other in a direction transverse to said stock.

3. In an apparatus for the draw-forging of elongated ductile metal stock wherein two pairs of die jaws are swingably mounted for eccentric symmetrical displacement transverse to said stock by a drive means, thereby deforming said stock transversely while forcing material thereof forwardly and thereafter returning to respective starting positions for repetition of the drawing operation,.

said pairs of jaws being angularly offset through an angle of about about the axis of said stock, the improvement which comprises:

respective die faces on each of said jaws having a ridge confronting said stock and longitudinally subdividing the respective face into a main-shaping surface and a smoothing surface successively engageable with said stock, said main-shaping surfaces of the jaws of each pair having a distance of closed approach less than the corresponding final dimension of said stock and said smoothing surfaces of the jaws of each pair having a distance of closest approach equal to said final dimension; and mechanism for alternately displacing said pairs of jaws repeatedly for the draw-forging of successive portions of said stock, thereby initially expanding said stock beyond said final dimension upon each engagement of said jaws with said stock for subsequent compression of the stock to said final dimension by said jaws.

References Cited in the tile of this patent UNITED STATES PATENTS 455,905 Thompson Iuly 14, 1891 535,446 Hammesfahr Mar. 12, 1895 773,197 Crawshaw Oct. 25, 1904 1,319,837 Brinkman Oct. 28, 1919 1,378,639 Warner May 17, 1921 1,549,527 Fielding Aug. 11, 1925 2,178,141 Frame Oct. 31, 1939 2,669,137 Smith Feb. 16, 1954 FOREIGN PATENTS 518,968 Belgium Apr. 30, 1953 478,082 Canada Oct. 30, 1951 427,910 Italy Dec. 2, 1947 502,034 Italy Nov. 26, 1954 

3. IN AN APPARATUS FOR THE DRAW-FORGING OF ELONGATED DUCTILE METAL STOCK WHEREIN TWO PAIRS OF DIE JAWS ARE SWINGABLY MOUNTED FOR ECCENTRIC SYMMETRICAL DISPLACEMENT TRANSVERSE TO SAID STOCK BY A DRIVE MEANS, THEREBY DEFORMING SAID STOCK TRANSVERSELY WHILE FORCING MATERIAL THEREOF FORWARDLY AND THEREAFTER RETURNING TO RESPECTIVE STARTING POSITIONS FOR REPETITION OF THE DRAWING OPERATION, SAID PAIRS OF JAWS BEING ANGULARLY OFFSET THROUGH AN ANGLE OF ABOUT 90* ABOUT THE AXIS OF SAID STOCK, THE IMPROVEMENT WHICH COMPRISES: RESPECTIVE DIE FACES ON EACH OF SAID JAWS HAVING A RIDGE CONFRONTING SAID STOCK AND LONGITUDINALLY SUBDIVIDING THE RESPECTIVE FACE INTO A MAIN-SHAPING SURFACE AND A SMOOTHING SURFACE SUCCESSIVELY ENGAGEABLE WITH SAID STOCK, SAID MAIN-SHAPING SURFACES OF THE JAWS OF EACH PAIR HAVING A DISTANCE OF CLOSED APPROACH LESS THAN THE CORRESPONDING FINAL DIMENSION OF SAID STOCK AND SAID SMOOTHING SURFACES OF THE JAWS OF EACH PAIR HAVING A DISTANCE OF CLOSEST APPROACH EQUAL TO SAID FINAL DIMENSION; AND MECHANISM FOR ALTERNATELY DISPLACING SAID PAIRS OF JAWS REPEATEDLY FOR THE DRAW-FORGING OF SUCCESSIVE PORTIONS OF SAID STOCK, THEREBY INITIALLY EXPANDING SAID STOCK BEYOND SAID FINAL DIMENSION UPON EACH ENGAGEMENT OF SAID JAWS WITH SAID STOCK FOR SUBSEQUENT COMPRESSION OF THE STOCK TO SAID FINAL DIMENSION BY SAID JAWS. 